Respect region_name in nova_compute

Signed-off-by: Oleg Bulatov <oleg@bulatov.me>

library/cloud/nova_compute

@@ -249,6 +249,7 @@ def main():
                               module.params['login_password'],
                               module.params['login_tenant_name'],
                               module.params['auth_url'],
+                              region_name=module.params['region_name'],
                               service_type='compute')
     try:
         nova.authenticate()